


Under the Night Sky

by undertailsoulsex



Category: Undertale (Video Game)
Genre: Ecto-Genitalia, Ecto-Penis, Ecto-Tongue, Ecto-Vagina, Fluff, Fontcest, Incest, M/M, Outdoor Sex, Sibling Incest, Soul Sex
Language: English
Status: Completed
Published: 2016-03-24
Updated: 2016-03-24
Packaged: 2018-05-28 18:28:09
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,429
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6340477
Author URL: https://archiveofourown.org/users/undertailsoulsex/pseuds/undertailsoulsex
Summary: <blockquote class="userstuff">
              <p>Papyrus and Sans enjoy each other's company under the night sky.</p>
            </blockquote>





	Under the Night Sky

**Author's Note:**

> Inspired by and based on tender-tepid-tea's comic found at http://tender-tepid-tea.tumblr.com/post/141529883012/i-tried-to-make-a-comic-hahahaha-there-are-so  
> You can find my tumblr at http://undertailsoulsex.tumblr.com if you want to see more NSFW soul sex art/fics.
> 
> I haven't written anything creatively in a long time, so hopefully I'm not too rusty at this.

Sans ran after Papyrus. The younger skeleton was bounding up the grassy hill, taking long strides with his long legs. Sans couldn’t understand how Papyrus had so much energy after the long day, but seeing the large smile stretched across his brother’s face made his heart beat in excited nervousness and put a spring in his own step.

Sans wasn’t sure what had inspired this trip. He and Papyrus had been working over the last month, helping other monsters build homes on the surface, including transporting materials and setting up infrastructure around Mt. Ebott. It was draining work, and even Papyrus had been lethargic as of late. For the last couple of weeks, both of the skeletons had come home, cooked a quick meal, maybe watched some television, and then had gone straight to bed. There was no time, no energy for puns, new recipes, or anything sensual.

So when Papyrus had burst through the door this evening, Sans had nearly fallen off the couch in surprise. The younger brother had marched right over to Sans, a slight orange glow on his face, and had boldly announced to Sans that they were going to go stargazing tonight. Before Sans had a chance to ask his brother about the sudden plan, Papyrus had rushed to grab a blanket from upstairs. Sans had smirked and grabbed his astronomy book before Papyrus had hurried out the door, calling to Sans to hurry up over his shoulder.

Papyrus reached the top of the grassy knoll first and spread the blanket on the ground. Sans trailed behind. As soon as he reached the top of the hill, he collapsed onto the freshly strewn blanket, panting from the exertion of running up the incline.

“not…that…i don’t think…this is a great idea…but why…did we have to…run up here…so quickly, bro?” Sans sputtered out between gasps.

“BECAUSE, SANS, UNDYNE TOLD ME THERE WAS GOING TO BE A METEOR SHOWER TONIGHT! I DID NOT WANT TO MISS IT!” Papyrus seemed giddy with excitement and was bouncing up and down, looking at Sans with glee.

Sans looked up at the sky. There was still faint light stretching from the hidden horizon. The sun had set only just over an hour ago, and the only visible celestial bodies were the evening star and a thinly-sliced crescent moon.

“bro, did undyne say when the meteor shower would start?” Papyrus stopped bouncing and looked confused. Sans lifted his face into a hesitant grin. “they don’t last all night, you know?”

Papyrus looked disappointed. He slumped down on the blanket next to Sans and placed his elbows on his knees.

“I AM SORRY, SANS.” He sounded embarrassed and upset. “I – WELL, I HAVE WANTED TO SPEND TIME WITH YOU LATELY. I THOUGHT THIS WAS THE PERFECT OPPORTUNITY.” He turned to Sans, a small smile and an orange blush on his face. “I KNOW HOW MUCH YOU LOVE THE STARS.” He faced away again and rubbed his arm. He lowered his voice – something he only did during his more intimate moments – and said, “I thought it would be fun.”

Sans paused. He had been so busy lately and he was realizing just how little time they had spent together over the past month.

He sat up and sloped against Papyrus’s shoulder and grinned. “you’re right, bro. it does sound like fun.”

Papyrus wrapped his arm around Sans and leaned his weight into his brother. With the same quiet tone he murmured, “We could look at the constellations until the meteor shower starts.” He shifted, moving Sans slightly. “That is, if you want to. I did not even think to bring food and you must be so tired after working all day and the stars aren’t even out yet, so I guess there really is no point to being out here, but –“

Sans placed his hand on Papyrus’s and the younger brother went quiet. “don’t worry. the stars will come out soon. and besides, i’m not tired, paps.”

It was true. As Sans stared out into the surrounding forested area, he realized that he was suddenly full of energy. They were alone in the region – they had built their home some distance away from the aboveground monster metropolis. They hadn’t wanted their home in the center of all the traffic and crowds.

Their isolation now sent shivers down Sans’s spine.

Sans leaned his face into Papyrus’s and kissed his cheek. The gesture caught Papyrus off-guard and when the younger skeleton turned to face Sans there was confused look on his face.

Sans wrapped his arm tighter around his brother’s shoulder and clinked his mouth against Papyrus’s in a skeleton kiss. Papyrus leaned into the kiss and wrapped both his arms around the older skeleton in an embrace.

It had been so long since they had shared a moment like this. Too long.

As they continued to kiss, Sans brought his left hand up to Papyrus’s back. He grazed the other skeleton’s ribs through his battle body, eliciting a shiver that reverberated down the younger skeleton’s body. Sans pulled his head away from his younger brother, a self-conscious smile gifting his blushed blue face. The pair stared at each other for a couple of minutes, love and adoration for one another written plainly in both of their expressions.

Papyrus deftly took his gloves off and quickly reached his hand down to the older skeleton’s shorts, firmly tugging the apparel to Sans’s knees. The sudden exposure to the cool evening air caused Sans to grip his brother tighter in his embrace. Papyrus ignored the motion and brought his hand to Sans’s now-exposed spine. He pumped his hand around the grooves, causing Sans to gasp and arch his spine.

“ah! paps!” he groaned, leaning into the taller skeleton’s shoulder. The older skeleton raised his hands to the cape around Papyrus’s neck and gracefully lifted the garment over the slim skeleton’s head and tossed it aside. Papyrus continued to drift his hand forcefully over Sans’s spine, causing him to gasp and moan every time the thin fingers grazed along the ruts and furrows.

Using his ecstasy to fuel his magic, Sans conjured a glowing blue tongue in his mouth. Moaning, he carefully slid his tongue over Papyrus’s slender neck. The lanky skeleton’s breath hitched as the tongue slowly ran over his sensitive cervical vertebrae. Sans licked tenderly, slowly working his way up Papyrus’s exposed neck until he reached his chin where he stopped to gaze at a blushing Papyrus, a smirk spread across his glowing blue face.

“why’d you stop, bro?”

Papyrus hadn’t realized that he had stopped his ministrations on Sans’s spine. He had unknowingly brought his shaking hands to his older brother’s neck. His hands were now pressed against his brother’s soft, cotton-lined hoodie, unconsciously holding Sans closer to him so that the smaller skeleton could better access his neck as he lathered him with kisses.

“heh,” Sans said as his grin grew even wider. “i guess that was a real tongue twister.”

Papyrus froze at the pun. Seeing the smirk stretched across his brother’s face, Papyrus decided he wouldn’t groan at Sans’s poor joke. Instead he’d show Sans just how much trouble his witty tongue – nyeh heh, he thought inwardly at his own delightful pun – had gotten him into.

Papyrus pushed Sans down onto the blanket-covered ground and gazed at Sans mischievously. He conjured his own orange tongue in his mouth, quickly pulling Sans’s shorts completely off his legs as he did so. Before Sans could react to his lower half becoming completely exposed to the elements, Papyrus bent down and grazed his tongue along his brother’s ilium.

“ngh!”

Sans’s smile quickly disappeared and was replaced with Sans’s open mouth, loudly moaning as Papyrus licked all along his pubic bone and carefully fingered the sacrum. Sans squirmed underneath Papyrus’s ministrations and it wasn’t long until he reflexively summoned genitalia around the taller skeleton’s finger and tongue.

Papyrus stood up and hurriedly pulled his own shorts off his body. Not having bothered to take off his boots, the pants snagged and tore in the rush to cast away the clothing.

But neither of the two focused on the lost apparel. They both stared at Papyrus’s own pelvic area as the lanky skeleton summoned his glowing orange length. The intensity of the glow lit up the immediate area, their bodies casting shadows in the grass around them.

A light breeze drifted over the hill, gently blowing the grass and sending shivers through the two skeleton’s bare bottom halves.

Papyrus dropped to his knees and pulled Sans’s pelvis into his lap, letting his older brother’s legs dangle over his hipbones. He rubbed his length along Sans’s slit teasingly, eliciting a low moan from the smaller skeleton. Papyrus rubbed the inside of the older brother’s femur gently as he looked up at Sans’s face, silently asking for permission to enter him.

Sans quickly nodded to the unasked question and moaned as Papyrus pressed his length inside him. He was already so wet, which caused Papyrus to slide in relatively deep upon his first thrust. Sans gripped the blanket underneath him with one of his hands and clenched the back of Papyrus’s head with the other. He scrunched his face in pleasure, letting his eyes press shut.

As Papyrus began to move against him, Sans lifted his legs into the air slightly, curling his toes in satisfaction. Their bones clanked together as Papyrus began to thrust more quickly. Sans’s mind was fogging at the ecstasy he felt below and he felt himself lose control as he began to meet Papyrus’s thrusts with his own smaller ones.

“Ah! Ah! Ah! Sans!”

Papyrus pulled his length almost completely out of Sans and plunged deeper than before. Sans kept his eyes shut completely as he felt himself give into the immense pleasure of moment.

“AH! oh god, paps!”

Papyrus had moved his head to Sans’s shoulder. He turned his head towards the side of Sans’s head, giving him a delicate skeleton kiss as he continued his movements below. Out of the corner of his eye he saw something that took his breath away.

“Ngh, Sans…” Papyrus moaned to the side of Sans’s head. The moan invigorated Sans and caused him to tighten below. The tightness made Papyrus lose his train of thought for a moment. He released another moan into the air, louder this time.

“AH!” Sans yelled again, as Papyrus thrust harshly in reaction.

Papyrus slowed his movements slightly, not wanting Sans to miss what he had seen.

“Sans. Please, open your eyes.”

It was difficult. Sans was too caught up in his own satisfaction. He slowly opened his eyes, gradually willing to wake his brain up from the distractions between his legs. Then he finally realized what he was seeing.

Above him were endless stars, twinkling in the dark sky. He had never seen so many of the blinking objects in the night sky. He swore he even saw a thin band of light streak across the sky, signaling a meteor, though it might have been his eyes playing tricks on his wishful mind. The vastness of the heavens left him feeling small and vulnerable on the top of the grassy knoll.

Sans’s mind was brought back to the present moment as Papyrus pulled Sans’s pelvis even closer to his own and thrust even deeper than before.

“ah! ah!” Sans shouted. “you’re amazing, bro!”

Papyrus nyeh-ed at the compliment, but his thrusts were becoming more desperate as he felt himself getting closer and closer to the edge. The younger skeleton knew that Sans wouldn’t reach an orgasm at the rate he was approaching his own release. He leaned up from his spot on Sans’s shoulder and pulled up Sans’s shirt and hoodie to expose his ribcage. Below the ribs, Sans’s soul glowed fiercely, casting even more light on the copulating duo. Papyrus reached into the ribcage and tenderly grasped the essence of his brother’s being, bringing it out into the open air.

“AAAH!” Sans ground his hips fiercely against Papyrus in reaction to the sudden feeling of the chilling night air touching his soul. “w-what – paps, why are you –?”

Papyrus continued to thrust his length deeply into Sans, hitting the end of the blue conjured genitalia, as he carefully brought the soul to his tongue and delicately licked the edges.

Sans’s voice gurgled in his throat as immeasurable pleasure gripped his body. He unknowingly began to thrust more harshly against Papyrus. Papyrus quickly changed his gentle licks into harsher tongue thrusts, plunging both his tongue into the delicate soul fiercely and his length into Sans’s depths.

Sans lost all control. He shouted and twisted his body, gripping the blanket below him even more tightly. His toes wound tightly as he felt the final throes of his pleasure reach him from Papyrus’s expert motions.

Papyrus thrust his entire length into Sans and the two came simultaneously. Papyrus felt Sans squeeze tightly around his length as he filled the cavity with warm orange liquid. At the same time, Sans’s soul released its melting magic, splattering the pair with white liquid that tinged with glowing blue magic.

As Papyrus felt the last spurt of liquid leave his conjured member, he collapsed onto Sans’s chest, not bothering to remove himself from Sans’s opening. Both of them panted, trying to catch their breath as their minds returned to reality.

They lay there for some time, each of them feeling the sticky liquid from Sans’s soul covering their bodies. They also felt the warmth of their magic below, as neither had felt the need to dismiss the genitalia when they felt so perfect, laying there, one inside the other.

Sans spoke first. “paps?”

“Mmm?”

“the meteor shower started.”

Papyrus turned his head to the side, pressing against Sans’s chest. The sky was filled with what appeared to be stars falling from the heavens, leaving streaks of light behind for half a moment before disappearing without a trace. Against the backdrop of the rest of the sky, speckled with distant stars, it was awe-inspiring.

“Wowie!” Papyrus exclaimed. He brought a hand to Sans’s chest and gripped it softly, trying to express the wonder he felt. 

“bro, i’m so glad you brought us up here.” Sans hugged his brother and looked down at the younger skeleton, smiling. “the sight is just too beautiful for words.”

The two of them remained in that position for the rest of the night, keeping each other warm as they watched the meteor shower into the early morning.


End file.
